Does gypsum increase crop grain yield on no‐tilled acid soils? A meta‐analysis

Abstract

Improving the chemical conditions for plant growth in the subsoil is especially difficult in no-till (NT) soil because of the low solubility of limestone. In this situation, gypsum may be recommended due to its ability to mobilize exchangeable Ca 2+ and other basic cations associated with SO 4 2− anions mainly in the soil profile, thereby alleviating Al toxicity. However, the response of crops to gypsum is contradictory and ranges from a substantial increase to a slight decrease in grain yield. In this work, a meta-analysis comprising 129 harvests of six different grain crops (930 observation pairs in all) was conducted to identify the conditions under which grain yield responds to gypsum and to establish criteria for optimal management of gypsum as an amendment for NT soils. Based on the results, cereals (maize [Zea mays L.], wheat [Triticum aestivum L.], white oat [Avena sativa L.], barley [Hordeum vulgare L.], and rice [Oryza sativa L.]) have a high probability (77-97%) of their grain yield being increased by gypsum application to soils, with Al saturation exceeding 5% in the 0.20to 0.40-m layer. The average increase in grain yield was 14 and 7% in crops growing in the presence and absence of water deficiency, respectively. A positive response of soybean [Glycine max (L.)Merr.] to gypsum was observed in water-deficient soils with Al saturation exceeding 10%. Under these conditions, the probability of a positive response of soybean was 88%, and the average yield increase was 12%. Therefore, gypsum application decreases Al toxicity to plants and increases crop grain yields as a result in NT soils with high Al saturation.

Soybean Agronomic Performance Does Not Change with Gypsum Application in a Cambisol Submitted to Water Restriction in Southern Brazil

“…According to current bibliographic research, Al saturation is the main parameter related to decision-making regarding gypsum use. The possible effects of increased yield occur mainly when the values are greater than 10% in water stress conditions or above 43% without water stress [12]. Although Al saturation in this study was above 50% in the 20-40 cm layer, soybean yield was not influenced.…”

“…With this regard, several authors emphasize the importance of soil correction in the subsurface for Al saturation reduction and Ca content increase. The objective is to improve soil chemical quality along its profile and enable better root development at depth, thus meeting plants' nutritional and water requirements, with positive yield responses [6,11,12,14].…”

“…Among the main grain crops, soybeans are the least responsive to gypsum application, especially compared to grasses [12]. According to current bibliographic research, Al saturation is the main parameter related to decision-making regarding gypsum use.…”

“…However, most of the information reported in the literature on this subject comes from studies conducted on Oxisols [12]. Therefore, there is a need for research to cover other soil classes, making it possible to extend recommendations and confirm the response patterns shown in the literature to other edaphoclimatic conditions.…”

Economic Potential of Rare Earth Elements in the Philippine Phosphogypsum

“…It has been shown to improve the plasticity, swell-shrink nature, and microstructure of the stabilized expansive soil(James & Pandian, 2016). Further, phosphogypsum can be mixed to produce anthropogenic soil or anthrosols that provides efficient growth medium and healthier biomass, which is excellent for growing high value crops and for afforestation to sequester carbon and combat climate change(Nichol, 2020;De Castro Pias et al, 2020).  The following utilization pathways are proposed to attain circular economy in phosphate fertilizer industry in the Philippines as shown in Figure4.…”